Some batches of polio vaccine used around 1960 were contaminated with SV40, a virus that in monkeys causes various cancers. Some researchers now claim that this contamination caused some cases of a certain cancer in humans, mesothelioma. This claim is not undercut by the fact that a very careful survey made in the 1960s of people who had received the contaminated vaccine found no elevated incidence of any cancer, since ___________.
<p>(A) most cases of mesothelioma are caused by exposure to asbestos<br/>(B) in some countries, there was no contamination of the vaccine<br/>(C) SV40 is widely used in laboratories to produce cancers in animals<br/>(D) mesotheliomas take several decades to develop<br/>(E) mesothelioma was somewhat less common in 1960 than it is now</p>
- Many Runagian senior citizens are no better off financially now than they were before the increase.The phrase “better off” is closest in meaning to________?
- The word "accidental" is closest in meaning to___________ ?
- Who can it be? I’ m quite ____ a loss to guess．
- The number of people flying first class on domestic flights rose sharply in 1990, doubling the increase of the previous year.
- The word "conspicuous" is closest in meaning to______ ?